Ingrowing toenails may cause pain and a loss of function, and lead to patients seeking treatment from a health practitioner [1
]. The prevalence of ingrowing toenails has been measured as 0.46% in a large population study in Korea [2
] and 2.45% in the United States [3
]. Bennet et al. [4
] reported 6.7% of conditions presenting to podiatric surgeons between July 1995 and June 1996 were ingrowing toenails. In the 2017 ACPS audit report [5
] this increased to 28.68%. While the increase could be explained by differences in the methodologies between these reports, both highlight that management of the condition constitutes a significant proportion of podiatric surgeons’ workload.
Contributing factors in the development of ingrowing toenails include nail cutting technique, nail shape (curvature), mechanical forces (either from ground reaction forces during gait, compressive forces from footwear, or structural malposition of the digits), hyperhidrosis, injury, and obesity [6
]. Because the nail often causes a break in the skin there is potential for pre-existing wound contamination.
A recent systematic review noted that the rates of surgical site infection following any type of foot surgery has been reported as between 0 to 9.4%, and that infection rate is lower where antibiotic prophylaxis is used [7
]. A clinical trial in 2007 by Bos et al. [8
] looking specifically at infection rates in partial nail avulsion procedures with phenolisation and excisional matrixectomies found no significant difference in the postoperative infection rates between the two approaches. Furthermore, this trial also determined that local administration of antibiotics did not reduce the risk of postoperative infection in either of the two surgical approaches. A retrospective audit of 80 patients receiving a partial or total nail avulsion by Modha et al. in 2016 [9
] found an overall postoperative infection rate of 3%.
In Australia, podiatric surgeons are registered specialist podiatrists, with an expanded scope of practice. Podiatric surgeons perform a range of procedures of the foot and ankle, including procedures for digital deformities, nerve entrapments, and ingrowing toenails [4
]. The aim of this study was to assess the type of ingrowing toenail surgery performed by podiatric surgeons, and to identify risk factors for infection.
In a previous clinical audit of podiatric surgeons, Bennett [4
] examined 786 patient files between July 1995 and June 1996. Bennett [4
] found 106 of 1575 (6.7%) reported procedures were for ingrowing nails. In this current study, we have found the frequency of presentation of ingrowing nails to podiatric surgeons to be higher (21.7% or all presenting conditions). These differences may be attributed to the differences in data collection. The current study reviewed data collected using the ACPS audit tool. Data is entered into this system in real time by Podiatric surgeons. Bennett [4
] reported data collected by a researcher retrospectively reviewing clinical records. This collection method may therefore have not identified all diagnoses of ingrown toenails within these records. Moreover, podiatric surgery has progressed since Bennett [4
] undertook the study, establishing itself as a mainstream surgical profession, leading to increased referral pathways and service access. For minor procedures that may have otherwise been performed by a general practitioner, or may have resulted in a long wait list time in the public system, podiatric surgeons provide an alternate pathway.
Similar to a recent study [2
], we have identified that ingrowing nails have a bimodal age distribution, with peaks in teenagers and people aged 40–50 years. Males were represented in greater numbers under the age of 40 and females were represented in greater numbers over the age of 40. The peak in prevalence of ingrowing toenails in teenagers could be attributed to greater physical activity in this age group, as an association between high levels of physical activity and ingrowing toenails in young males has been previously been demonstrated [15
]. Poorer nail cutting practices and hyperhidrosis may also account for the higher rates of ingrowing toenails seen in this population [6
]. The peak seen in the 40–50 year age group and the greater representation of women in this group could be accounted for by the increased prevalence of foot deformities (such as hallux abducto valgus) in older populations and females [16
]. Such foot deformities have been described as a risk factor for the development of ingrowing toenails [2
]. Older populations, in particular older females, are also more likely to wear ill-fitting shoes [17
] that create compression forces on the toenail and play a role in the development of ingrowing toenails [6
As described by Levy [3
] and Cho [2
], females represent a greater proportion of people affected by ingrowing nails, although ingrowing nails are also prevalent in younger males. However, Menz et al. [18
] found that more nail procedures were performed for males than females by private surgeons. Our results showed that women were more likely to have surgery for an ingrown toenail than men, accounting for 57% of patients undergoing surgery for ingrowing toenails. In addition to the presence of foot deformity and poor footwear, the greater number of women undergoing nail surgery could be attributed to the fact men may be less likely to access health care [19
In this current study, we identified that the rate of infection is higher for people undergoing procedures for ingrowing nails, than those undergoing procedures for other foot pathology. However, the rate of infection is lower than that reported in a similar study exploring postoperative infection after excisional toenail matrixectomy [20
]. The elevated rate of infection may be due to the presence of pre-existing wound contamination or infection.
Alternatively, infection rates may be elevated due to the perceived ‘less-serious’ nature of nail procedures compared to surgeries of bone and joint. This perception could potentially reduce the likelihood of antibiotic prophylaxis, or lead to procedures being performed in office-based rather than hospital facilities where intravenous antibiotic prophylaxis is available. Further, infection rates may be elevated because of reduced patient adherence to postoperative instructions. Given the high number of procedures performed by podiatric surgeons in an office setting, and the increased infection rate in this group, podiatric surgeons should consider the procedure location, and antibiotic prophylaxis, in their decision-making process.
The use of antibiotics in in the surgical management of ingrowing nails is unclear. Córdoba-Fernández et al. [21
] recommended the use of prophylactic antibiotics only in infective ingrowing toenails. A Cochrane review revealed that the use of antibiotics has not been shown to result in a difference in infection rates [22
]. Using a similar dataset, a prospective cohort study by Butterworth et al. [11
] showed that the use of perioperative antibiotics in foot and ankle surgery may reduce the risk of infection. However, Butterworth et al. [11
] did not separate their study population into specific procedure groups. Consequently, whether antibiotic prophylaxis reduces infection rates following ingrowing toenail surgery may be unclear. However, considering that many ingrowing toenail procedures are performed by podiatric surgeons under local anaesthetic, in office settings, where perioperative antibiotics may not be available, changes to practice should be considered to reduce infection rates in this population. Given that peri-operative antibiotic prophylaxis is standard procedure in hospitals, patients undergoing sharp excisional ingrowing nail surgery should be admitted for these procedures.
Our current study showed that the choice of procedure for management of ingrowing nails is associated with patient age and ASA status. Patients who underwent radical excision were on average older, and more likely to have systemic disease than those who underwent wedge or partial resection. This could be due to increased concern regarding healing times following chemical ablation in the older patient with systematic disease, or concern regarding long term aesthetics for the younger person. Alternatively, wedge and partial excisions may commonly be utilised as an earlier line of treatment. Ingrowing toenails of greater severity or associated with gross deformation or disease of the nail, or ingrowing nails recalcitrant to treatment, may require radical nail bed excision. Procedure choice may be dependent on the presence of peri-ungual soft tissue variation seen around the nail fold, such as ungelabia and onychomatrixoma. Procedure choice may also be due to associated bone pathology such as subungual exostoses, which is being addressed concomitantly. Furthermore, a surgeon may choose an excisional matrixectomy over a chemical procedure to aid direct visualisation of target tissue when revision surgery is being performed in the case of primary procedural failure.
In the current study, a higher infection rate has been associated with radical excision procedures. The nail and nail folds have been identified as the most heavily contaminated area of the foot and ankle and are difficult to decontaminate [23
]. Radical nail bed excision potentially disseminates debris from the nail folds, contaminating subcutaneous tissue and periosteum overlying the distal phalanx. Radical bed excision may also be a procedure of choice for more severe ingrowing toenails with active or unresolved paronychia, hyper-granulation tissue and bone deformity. The higher infection rate may be attributed to an unresolved infection at the time of surgery. However, patients undergoing radical excision were more likely to be older, have systemic disease, and have the procedure performed in an office setting. Consideration should, therefore, be given to admitting these patients to a day surgery facility, especially those with systemic disease who are aged over 60.
This study has identified that some procedures (wedge resection) for ingrowing nails performed in an office setting are associated with a higher rate of infection. This could be due to the greater emphasis on the design and maintenance of hospital and day surgery facilities for pathological microorganism control. However, those patients undergoing procedures in office settings were also older, and more likely to have systemic disease. A question raised in this study is why are older patients with systemic disease more likely to have a procedure performed outside a hospital setting? It could be convenience, cost (including lack of Medicare and insurance funding), or a combination of these and other factors. Further research is required to answer this question. Of interest to the podiatric profession is that no increase in infection risk was identified for partial resection (with phenol) in an office setting. This result is likely due to partial resections being less invasive, not involving skin incisions, or bone. Moreover, phenol has been shown to provide anti-bacterial activity against both gram positive and gram negative bacteria [24
In this current study, we have shown that certain population groups have a higher reported rate of infection. However, due to the low rate of infections, we were unable to perform multivariate regression analysis to control for other factors. For example, whilst the rate of infection is higher in patients who underwent radical excision of nail bed, the average age of a patient who had this procedure was also higher, and they were also more likely to have systemic disease.
There are limitations in this study which could have resulted in misreporting of infection rates. Infection could have been identified by the surgeons based on clinical manifestations only, and did not require microbiological confirmation in all cases. Further, it is possible that some patients would present to other members of their health care team (for example general practitioner) in the first instance of a minor post-surgical infection. Also, it is possible that infection rates were affected by those patients with a pre-existing infection. Further, no information was available regarding the use of antibiotics.
The follow up period for this study was 30 days and did not consider whether the procedure resulted in permanent resolution of the patient’s condition. It is possible that patients who present to podiatric surgeons have had previous ingrowing toenail surgery, or more complex health concerns than those patients who present to a non-specialist podiatrist, therefore, these results should be interpreted with caution outside of these settings. However, a key strength of this research design is that it measures real-world practice.
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